Scott River Water Trust con't from page 36
For the past eight months we have been collaborating with a working group that consists of the area's most qualified individuals to bring habitat restoration and enhancement efforts to nearly three contiguous miles of the mainstem Scott River. It’s a project that has enormous fisheries potential, and is a great opportunity for restorationists working in the Scott Basin to take our efforts and partnerships to the next level. It’s also something that would not be possible without the cooperative effort started by Andrew and myself.
CalTrout has displayed fairness and honesty and the opportunities originating from our willingness to work together will only benefit the watershed. If people sit down and talk about their positions and why they take the stances they do, chances are some common ground will be found. I know that sounds rudimentary but communication doesn’t always happen. Andrew and I took the time to listen and be open-minded, and I think fish, water and people in the Scott will be better for it.
Fish and Flows contintued from page 47
Scouring:
High water events are also good in that they clean rivers out. Many rivers build up different types of algae during the warm summer months, especially tail water fisheries that have fairly stable flows controlled by dams. In the past several years, evasive didymo slime has become a real problem for many of California’s rivers. Didymo and other types of algae can completely take over the sub-straight and choke out a vast majority of insect life as well as deplete oxygen levels which will bring water
temperatures up. A good high water event is needed
to break up and flush out algae. Clean rocks and pebbles are much better for macro invertebrates. Salmonids also require clean gravel to spawn. High water events also clean out debris like leaves and sticks that may have built up over the dry season.
Sediment Transport:
Sediment transport is an important part of stream hydrology. High water events are needed to get the rocks and dirt moving. Sometimes high flows can scour pools out and create depth which is preferable to fish for holding habitat. Other times it can work the other way and deep pools may be filled in with sediment making them shallow. For the most part though, high flows are good for moving the river around and flushing sediment.
Habitat Complexity:
High water events can also be good for habitat complexity in streams and rivers. Surprising to some, wood is one of the absolute best materials for fish habitat. It’s provides cover from predators and also promotes macro invertebrate growth. Often, trees fall into or near rivers. High water events are needed to either push the wood out of the stream channel so fish can maintain passage or to pull new wood into the stream channel creating new habitat. Wood that has fallen during the summer often needs high flows to scour out around it, which creates pools and holding areas for fish under logs and root wads. This habitat is critical for both adult salmon and steelhead as well as smolts.
Floodplains:
According to studies conducted by CalTrout and UC Davis, floodplains are some of the most productive
areas for juvenile fish rearing habitat. When the
water spreads out, it slows down and the young fish don’t have to work so hard to fight the currents. There’s also much greater access to food on the floodplains. The shallow water acts as a lens allowing light to penetrate more off the bottom which promotes faster and more growth of organisms that provide food for fish. Also, as the water rises it inundates lots of land dwelling insets which also become food for fish. Smolts often only have access to floodplains during extreme high water events. Almost every river in California used to have a floodplain. Now, many lower river areas have been levied off to protect bottom lands for agriculture and other development. Extreme high water events allow fish to access flood plain areas that are otherwise inaccessible at normal flows.
In conclusion, high water events are a part of the natural system our native fish have adapted to use. They are a necessary part of the ecosystem in California and incredibly beneficial to native fish, especially salmon and steelhead.
Mike Wier
.